A vehicle headrest, typically provided in a car or truck, is known having a vehicle-mounted support typically fixed in a seat back and a cushion against which the occupant of the seat can rest the back of his or her head. This headrest provided some protection against whiplash by preventing the occupant's head from snapping too far back when rebounding after a front-end collision or simply moving back in a rear-end collision.
Some adjustability in the vehicle travel direction can be provided as shown in German 3,900,495 or EP 0,974,484 by allowing a portion of the headrest to be shifted forward and rearward. Alternately as described in German 3,109,592 it is possible to provide structure allowing the entire cushion to be shifted forward and rearward. U.S. Pat. No. 4,278,291 described a headrest that is biased forward by springs to provide cushioned whiplash protection.
It is also known to provide some sort of mechanism to automatically shift the cushion forward in a collision so as to limit rearward travel of the seat occupant's head, especially in a situation where there is an air bag that might press the seat occupant back with some force. Above-cited German '495 shifts a part of the cushion forward and locks it in place in a collision, and above-cited EP '484 has a complex set of arms that solidly lock the cushion in its front-most position when activated in a collision.
The known such crash-responsive headrests are typically fairly complex. They do not allow the headrest to be easily reset in a middle or rear position after crash actuation. Furthermore the crash-responsive actuating system often has a number of interlinked parts that cannot be counted on to work after having sat, unused for years. Finally the known systems are expensive to manufacture and replace.